The compound zopolrestat, 3,4-dihydro-4-oxo-3-(5-trifluoromethylbenzothiazol-2-ylmethyl)phthalazin-1 -ylacetic acid, is known, for example from commonly assigned U.S. Pat. No. 4,939,140 to Larson et al., together with a number of compounds related thereto, to have utility as aldose reductase inhibitors. Zopolrestat has the structure ##STR2## and, as an aldose reductase inhibitor, is useful in the treatment of certain chronic complications arising from diabetes mellitus.
U.S. Pat. No. 4,492,706 to Kallai-Sanfacon teaches that certain aldose reductase inhibitors such as N-[(6-methoxy-5-trifluoromethyl-1 -naphthalenyl)thiono]-N-methylglycine (commonly known as tolrestat) function as antilipogenic agents in mammals.
EP 0 310 931 A2 discloses the use of a group of compounds, as antilipogenic agents in poultry, including tolrestat, having the formula ##STR3## wherein R is an alkyl group of 1-6 carbons, R' is hydrogen or a saturated hydrocarbyl group, R" is hydrogen, hydroxy, or an alkoxy group of 1-6 carbons, R'" is hydrogen or ((CF.sub.2).sub.n CF.sub.3, X is sulfur or oxygen, and n is zero or an integer of at least one. This EP application further discloses a poultry feed containing an antilipogenic agent having the above formula.